Simple answer. Asuming you use the module system.. If you don't I can't help you..
Go into module_simple_triggers.py and then find, and delete this:
#Pay day.
(24 * 7,
[
(call_script, "script_calculate_player_faction_wage"),
(assign, ":total_wages", reg0),
(store_add, ":total_debt", ":total_wages", "$g_player_debt_to_party_members"),
(try_begin),
(gt, ":total_debt", 0),
(jump_to_menu,"mnu_pay_day"),
(try_end),
(assign, "$g_cur_week_half_daily_wage_payments", 0),#Reseting the weekly half wage payments
]),